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Abstract: The island of Gran Canaria is located in the eastern Atlantic, to the west of the Saharan Desert, and, as a result of its proximity, is regularly affected by Saharan dust. When this weather condition occurs (haze conditions) the particulate/aerosol accumulation rate was lightly higher than under non-haze conditions (5.4±3.8mgm−2 h−1 versus 4.3±2.1mgm−2 h−1). To quantify the contribution of airborne Saharan dust to soil development in northeastern Gran Canaria, aeolian dust was collected weekly at different altitudes and distances from the coast during a year in a series of collection plots. Mean values of dust accumulation rates decreased with increasing altitude (from 79 to 17gm−2 yr−1). The mineralogy of airborne dust, identified by XRD, was quartz, Mg-calcite, calcite, feldspars, dolomite, magnetite, aragonite, halite, and minor amounts of illite, kaolinite-chlorite and palygorskite. Quartz is considered allochthonous because it is not present in the volcanic substrate of the island. However, the difference in quartz concentration from haze to non-haze conditions was only 10% higher. This suggests an external source, but does not preclude a recycled origin. The recognition of well shaped dolomites, observed by SEM-EDX in collected dust samples and in soils samples of the lowest altitude plot, indicate an edaphic origin, but are later recycled as an airborne component. [Copyright &y& Elsevier]

SEM Images of atmospheric quartz particles. Provenance may justify differences in shape parameters. [Display omitted] • The composition, morphology, and provenance of spring atmospheric dust are heterogeneous. • Atmospheric dust features depend on their provenance. • SEM morphology of atmospheric quartz particles is a provenance fingerprint. • Quartz morphoscopy is a new technique to understand atmospheric dust provenance. Dust in the Earth́s atmosphere is increasing, particularly in southern Spain. The study of dust properties allows for a hypothesis on the origin and provenance of dust. This study characterised atmospheric dust deposited in the city of Granada (south of Spain) during three spring periods (samples 4PA, 16PA, and 28PA, collected in 2012, 2013, and 2014, respectively). The aim was to ascertain dust characteristics and genesis using a set of methodological techniques. The backward trajectories study separated the samples into two groups: scarce Saharan influence (sample 16PA, 6% of backward trajectories are from, or have passed through, Africa) and greater influence (samples 4PA and 28PA, 26% and 33%, respectively). This grouping was verified by the rest of the properties analysed, namely, PM10 concentration, deposition rates, grain size, mineralogy, and elemental composition (minor, including rare earth elements). In addition, mineral quartz showed differences in particle morphology and surface microtextures. The mineralogical and geochemical studies of our samples have proved similarities with other dust collected in Granada and soils from the Iberian Peninsula. The principal component analysis of the quartz shape parameters insists on the differentiation of these groups. We propose the morphoscopy of quartz grains (a significant component of atmospheric dust) as a fingerprint of provenance. [ABSTRACT FROM AUTHOR]